Pressure relief valve unit

ABSTRACT

A valve unit attachable to a fluid type transformer for automatically relieving it of excessive gas pressure developing therein. The unit includes a spring loaded control valve adapted in response to excessive pressure from the transformer to pop open and allow the pressurized gas to dump through an escape tube. A closure, protectively closing the escape tube against entry of moisture and dust, drops from the tube to a depending position under force of the escaping gas to present a brightly colored signal to inspectors that the transformer is possibly malfunctioning.

United States Patent 91 Brindisi 1 Oct. 29, 1974 [54] PRESSURE RELIEF VALVE UNIT 2,904,616 9/1959 Koepke et al 137/469 X [76] Inventor: Frederick J. Brindisi, 1385 Fairport f f ffff jjjjjj; 3 7 -1 P311119", NY 14450 3,425,444 2/1969 .loncs i. 1.37/46) x J 2 122,645 5/l945 Brown |37/527.4 X [21] AppL No: 369,408 FORElGN PATENTS OR APPLICA HONS 706,112 3/1954 Great Britain 137/469 Related U.S. Application Data [62] Division of Scr. No. 219.274, Jan. 20, 1972, Primary Examiner-Alan Cohan dbflndoned- Assistant Examiner-Gerald A. Michalsky Attorney, Agent, or FirmStephen J. Rudy [52] U.S. Cl 137/557, 137/467, 137/5274,

137/543, 137/613 57] ABSTRACT [51] Int. Cl. F16k 37/00, F16k 17/08 A Valve unit attachable to a fluid type transformer for [58] Field of Search 137/467 469 512 3 527 137527 4 542 13 automatically relieving it of excessive gas pressure de- 61 veloping therein. The unit includes a spring loaded control valve adapted in response to excessive pressure from the transformer to pop open and allow the [56] References cued pressurized gas to dump through an escape tube. A UNITED STATES PATENTS closure, protectively closing the escape tube against 509,351 11/1893 Maertens 137/542 X entry of moisture and dust, drops from the tube to a 1,157,196 lO/l9l5 Philp 137/542 depending position under force of the escaping gas to fi in? present a brightly colored signal to inspectors that the orn l 2,506,737 5/1950 Paquin 137/613 X transformer is posslbly malfunctlomngu 2,879,794 3/1959 Costello 137/543.13 X 5 Claims, 3 Drawing Figures PRESSURE RELIEF VALVE UNIT BACKGROUND OF THE lNVENTlON This application is a division of US. Pat. application Ser. No. 219,274 filed Jan. 20, 1972, now abandoned, for a Pressure Relief Valve Unit.

This invention is concerned with a valve unit adapted to be connected with a container for automatically relieving the latter of excessive pressure of gases that might develop therein.

While the valve unit of the present invention is subject to various applications, it is designed for and especially suited for use in association with the tank of a fluid type electrical transformer such as one that is located outdoors or is mounted upon a pole.

Transformers of the fluid type are likely, when overheated or malfunctioning, to develop gases in the tank which may build up to undesirable excessive pressure. It is the purpose of the valve unit of the present invention when connected to the container to be responsive to a predetermined gaseous pressure rise in the transformer so as to effectively relieve the transformer of such pressure. It is a further purpose of the present valve unit to provide means which will function automatically upon operation of the unit to visibly indicate to those concerned with proper operation of the related transformer that excessive pressure had for some reason developed in the transformer and has been relie'ved.

A particular advantage of the valve unit of the present invention results from the manner of association of a control valve therein relative to its seat and relative to a relief chamber in which it is movable whereby, when the valve is unseated, pressure gases from the transformer are enabled to pass rapidly and unimpeded through the chamber to an escape tube.

Another advantage results from the manner of the association of a closure with the escape tube, which closure serves in anormally closed condition to protectively seal the internal valve mechanism of the unit from undesirable dust and moisture. The closure is so arranged that it is caused to readily drop free of the escape tube under pressure of gases entering the unit from'the transformer. The closure has a retaining connection with the unit whereby, when it is dropped from the escape tube, it depends externally of the latter to present a brightly colored surface as a signal that the transformer is in need of inspection.

Other advantages of the invention will appear as the specification is read in conjunction with the accompanying drawing in which the invention is illustrated.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing:

FIG. 1 is a sectional view of a pressure relief valve unit illustrating a first embodiment of the invention;

FIG. 2 is a section on line 22 of FIG. 1; and

FIG. 3 is a bottom plan view of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENT The pressure relief valve unit illustrated in the drawing includes a hollow housing having a main body portion 11 defining an internal cylindrical chamber 12 in which a spring loaded valve 13 is axially slidable relative to a valve seat 14 provided about the inner end of an inlet passage 15. The inlet passage which is of a smaller diameter than that of chamber 12 is defined by a spigot or pipe nipple 16 extending axially from the forward end of the housing. A threaded end of the nipple is intended to be connected in a port of the tank 18 (broken line) of a fluidtype electrical transformer for the purpose of relieving the latter of excessive gas pressure that might develop therein. Flats 19 about the body provide a surface to which a wrench may be applied for mounting the unit to an associated tank.

The valve chamber 12 is closed at its rear end by means of a circular cover plate 21. The plate is rigidly held seated upon an internal annular shoulder 22 of the housing by means of an end lip 23 of the housing turned inwardly, as by peening, upon the back of the plate.

A short depending escape tube 24 at the underside of the housing provides a relief passage 25 connecting the valve chamber with atmosphere. Passage 25 is of substantially greater diameter than that of the inlet passage 15 so as to allow an uninhibited and rapid escape of fluid from the valve chamber.

The valve has a circular head 26 which is constantly urged to closed condition upon the valve seat by the force of a return spring 27. The latter is limited be,- tween an annular shoulder of the valve head and the inner face of the cover plate 21.

The valve is movable axially of the chamber relative to its seat and is supported in this movement by means of an axially extending cylindrical tall or stem portion 28 which has sliding movement in an axially aligned sleeve 29 defined by a forwardly extending stem of the cover plate. A port (not shown) may be provided in the sleeve to avoid undesirable gas becoming trapped behind the valve stem.

The relation of the valve to the valve chamber and to its seat is designed to obtain a rapid dumping or exhaust of pressure fluid to the escape tube following opening of the valve. To this end, the valve chamber 12 is of greater diameter than that of the valve head 26. Lengthwise of the wall surface of the valve chamber extends a group of equally spaced radially depending ribs 31 (here three) which serve as a guide for the head of the valve as the latter is moved to and from its seat. The ribs, together with the support provided by the sleeve 29 to the valve stem 28, serve to stabilize the valve in its axial movement. The valve head presents a broad peripheral bearing surface to the ribs, which further serves to stabilize the valve in its movement.

The recessed areas 32 of the housing defined between the ribs are immediately brought into direct communication with the inlet passage 15 when the valve is forced from its seat by excessive gas pressure developing in the associated transformer. By means of this construction, pressurized gas from the inlet passage flows rapidly around the open valve into the recessed areas of chamber 12 from where it rapidly dumps through the escape tube 24 to atmosphere.

The valve is designed relative to its seat so that when a predetermined pressure of transformer gas in the inlet passage 15 is exerted upon the valve, the latter will suddenly pop open and rapidly move axially backward into chamber 12 a substantial distance from its seat. This allows an unimpeded flow of pressurized gas from the inlet passage into the chamber. To this end, the valve seat 14 is in the form of a rounded bead formed about the inner end of the inlet passage. This bead projects slightly into chamber 12. In addition, the valve head 26 is of a greater diameter than that of the inlet passage.

By means of this advantageous construction, as gas pressure builds up sufficiently against the smaller diameter area of the valve head that is exposed to the inlet passage to move or crack the valve slightly from its seat against the load of its spring, the pressurized gas then leaks around the bead defining the valve seat and acts over the greater diameter area of the valve head. The rapidly developing pressure over the valves entire forward surface forces the valve to pop open or abruptly move inwardly against the force of its spring and thereby allows a free and unimpeded dumping or flow of the in-rushing fluid to the escape tube.

Following relief of the pressurized gas from the escape tube, spring 27 relaxes to return the valve to its seat. A circular rubber gasket 33 seated in a corresponding recess of the valve head cushions the valve as it re-engages its seat under the force of the return spring.

Indicator means 34 that is visible from a distance is automatically releasable from the escape tube to a depending position (broken line, FIG. 1) to indicate to those concerned that the valve has blown, that is, had been operated by excessive pressure of gases developing in the associated transformer. I

The indicator means 34 is in the nature of a closure or hinged plug in the escape tube. It comprises an annular base plate 35 from the inner face of which axially extends a short tubular portion 36 of lesser diameter. The plug 34 has a normally closed condition in which its tubular portion 36 is received in a correspondingly reduced diameter portion 37 of the escape tube, and the base plate 35 is seated upon an internal shoulder of a relatively larger diameter area 38 of the escape tube. An O-ring 39 aboutthe tubular portion frictionally engaging the wall of the escape tube provides sufficient resistance to prevent the plug from dropping to open condition under its own weight. A lug 41 (FIGS. 1, 3) extending from the periphery of the plug is pivoted upon a hinge pin 42 in a lateral recess 43 of the escape tube. In its closed condition, the plug seals the chamber against entry of dirt and moisture to the valve mechanism. This is of advantage since the valve unit is exposed to the various elements of the weather when attached to a transformer mounted upon a pole.

The hinge pin 42 extends through a vertical lost motion slot 44. The slot is of an axial dimension that is adequate to allow the tubular portion 36 of the plug to be dropped axially out of the reduced diameter area 37 of the escape tube into the larger diameter area 38 under pressure of gas entering the valve chamber. When this happens, the plug 34 will swing on its hinge angularly downward and out of the escape tube to a depending vertical position (broken line, FIG. 1), hanging from its hinge pin. A brightly colored surface 45 of the plug then becomes visible for a considerable distance to indicate to those concerned the need of inspecting the associated transformer for possible trouble.

A tapped hole 46 is provided in the housing for securing by means of a screw an electrical ground wire to the housing.

What is claimed is:

l. A pressure relief valveunit for automatically relieving a container of excessive pressure of gas developing therein, comprising a housing having an internal chamber, a pipe nipple extending from one end of the housing for coupling the unit to the container, the nipple defining an inlet passage to the chamber for conducting pressurized gas from the container into the chamber, a valve seat defined about the inner end of the passage at its juncture with the chamber, a valve movable axially in the chamber relative to the seat, a spring biasing the valve to a closed condition upon the seat, the valve being movable from its seat upon development of a predetermined pressure of gas in the pipe nipple, and an escape tube depending from the underside of the housing defining a relief passage communieating the chamber with atmosphere; wherein the chamber is axially aligned with the inlet passage and is of a greater diameter, a group of circumferentially spaced ribs extend lengthwise of the wall of the chamber and depend radially for guiding the valve as it is moved relative to the seat, the ribs defining between each other radially recessed areas having direct communication with the relief passage of the escape tube, and the recessed areas having direct communication with the inlet passage upon unseating of the valve, wherein the housing has a rear closure wall provided with a sleeve extending axially forwardly into the chamber, and the valve has a circular head that is engageable with the seat and is provided with a rearwardly extending stem slidably received in the sleeve; and wherein a plug closure is frictionally engageable in the tube for closing the relief passage, the plug closure whenin closed position being adapted under pressure of fluid entering the chamber to drop out of the relief passage, the plug closure having when in closed condition a position entirely within the tube, and lost motion hinge means connected with the plug closure within the tube adjacent a bottom open end of the tube which allows movement of the plug closure from a position closing the passage to a position depending externally of the bottom end of the tube.

2. A pressure relief valve unit as in claim 1, wherein the seat is defined by an annular bead about the inlet passage projecting into the chamber, which bead spaces the valve in its seated condition from a wall area of the chamber adjacent the bead.

3. A pressure relief valve as in claim 2, wherein the valve has a circular head provided with a resilient gasket that is seated in a forward face thereof and is engageable with the seat.

4. A pressure relief valve as in claim 3, wherein the forward face of the valve is of greater diameter than that of the inlet passage and that of the bead defining the seat.

5. A pressure relief valve unit as in claim 1, wherein the plug has a brightly colored inner surface which is visible externally of the escape tube when the plug is depending from its hinge. 

1. A pressure relief valve unit for automatically relieving a container of excessive pressure of gas developing therein, comprising a housing having an internal chamber, a pipe nipple extending from one end of the housing for coupling the unit to the container, the nipple defining an inlet passage to the chamber for conducting pressurized gas from the container into the chamber, a valve seat defined about the inner end of the passage at its juncture with the chamber, a valve movable axially in the chamber relative to the seat, a spring biasing the valve to a closed condition upon the seat, the valve being movable from its seat upon development of a predetermined pressure of gas in the pipe nipple, and an escape tube depending from the underside of the housing defining a relief passage communicating the chamber with atmosphere; wherein the chamber is axially aligned with the inlet passage and is of a greater diameter, a group of circumferentially spaced ribs extend lengthwise of the wall of the chamber and depend radially for guiding the valve as it is moved relative to the seat, the ribs defining between each other radially recessed areas having direct communication with the relief passage of the escape tube, and the recessed areas having direct communication with the inlet passage upon unseating of the valve, wherein the housing has a rear closure wall provided with a sleeve extending axially forwardly into the chamber, and the valve has a circular head that is engageable with the seat and is provided with a rearwardly extending stem slidably received in the sleeve; and wherein a plug closure is frictionally engageable in the tube for closing the relief passage, the plug closure when in closed position being adapted under pressure of fluid entering the chamber to drop out of the relief passage, the plug closure having when in closed condition a position entirely within the tube, and lost motion hinge means connected with the plug closure within the tube adjacent a bottom open end of the tube which allows movement of the plug closure from a position closing the passage to a position depending externally of the bottom end of the tube.
 2. A pressure relief valve unit as in claim 1, wherein the seat is defined by an annular bead about the inlet passage projecting into the chamber, which bead spaces the valve in its seated condition from a wall area of the chamber adjacent the bead.
 3. A pressure relief valve as in claim 2, wherein the valve has a circular head provided with a resilient gasket that is seated in a forward face thereof and is engageable with the seat.
 4. A pressure relief valve as in claim 3, wherein the forward face of the valve is of greater diameter than that of the inlet passage and that of the bead defining the seat.
 5. A pressure relief valve unit as in claim 1, wherein the plug has a brightly colored inner surface which is visible externally of the escape tube when the plug is depending from its hinge. 